Dispersing clays, pigments and the like with amino

ABSTRACT

The disclosure is directed to the use of water-soluble amino diphosphonates as deflocculating agents for finely divided solid materials in an aqueous dispersion, slurry and the like, especially as deflocculating agents for the preparation of high solids, low viscosity slurries of pigments and clays for use in paper coatings. The useful amino diphosphonates are represented by the following formula WHERE R is an alkyl group of one to five carbon atoms, phenyl or benzyl and where x is 0 or 1 and where each M is independently selected from the group consisting of hydrogen, alkali metal, alkaline earth metal, and ammonium.

United States Patent 1 Hoover et al.

[ Jan. 30, 1973 DISPERSING CLAYS, PIGMENTS AND THE LIKE WITH AMINOAssignee:

Filed:

Inventors: Merwin Frederick Hoover, Pittsburgh; Gloria DiMarcoSinkovitz, Bridgeville, both of Pa.

Calgon Corporation, Pittsburgh, Pa.

Nov. 18, 1970 Appl. N0.: 90,857

US. Cl ..106I308 N, 106/72, 106/309 Int. Cl. ..C09c l/42, C09c 3/02Field of Search..l06/308 N, 72, 309; 252/8.5 C;

I References Cited UNITED STATES PATENTS Blaser et al ..252/l80 lrani etal. .Q ..252/8.5 lrani et al. ..252/8.S Crutchfield ..260/502.5

Primary Examiner-Delbert E. Gantz Assistant Examiner.|. V. HowardAttorney-William L. Krayer and Herbert .l. Zeh, Jr.

[57] ABSTRACT The disclosure is directed to the use of water-solubleamino diphosphonates as deflocculating agents for finely divided solidmaterials in an aqueous dispersion,

f slurry and the like, especially as deflocculating agents for thepreparation of high solids, low viscosity slurries of pigments and claysfor use in paper coatings. The useful amino diphosphonates arerepresented by the following formula I 9 Claims, No Drawings DISPERSINGCLAYS, PIGMENTS AND THE LIKE WITH AMINO BACKGROUND OF THE INVENTION Thisinvention is directed to stable aqueous dispersions of finely dividedsolids such as clays, pigments and the like. More particularly, thisinvention is directed to the use of water-soluble amino diphosphonatesasdeflocculating agents for preparing stable aqueous dispersions offinely divided solids.

Many industrial processes employ aqueous suspensions or slurries inwhich water is used as a vehicle for conveying solids. In addition, manyconsumer products are aqueous dispersions of finely divided solids. Someexamples of the industrial processes are the wet processing of cement,oil well drilling muds, kaolin processing, and pigment and clay slurriesfor paper coatings. An example of widely accepted consumer products arethe latex paints. In all of the above processes and products it isdesirable,if not necessary, to employ a dispersant to maintain thefinely divided solids in a deflocculated'state and to alter therheological properties of the system. For example, pigments and claysused for paper coatings have long required the employment of dispersantstoensure a coating color with a workable viscosity. It is highlydesirable to use a pigment or clay coating color having as high a solidscontent as possible. However, without a dispersing agentthe coatingcomposition cannot be practicallyhandled and still have a desirable highsolids content. Yet, when a deflocculating agent is utilized, it ispossible to prepare high solids, low viscosity pigment and clay slurriesfor use in coating colors.

In the past, various compounds have been used as deflocculating agents.For example, one class of compounds that has gained widespread use asdispersants is the molecularly dehydratedinorganic phosphates. SeeHansen, U.S. Pat. No. 2,750,299, which discloses the use of a sodiummetaphosphate glass to disperse calcium carbonate. More recently,organic phosphates have been employed as deflocculating agents. Forexample, see Lyons et al., U.S. Pat. No. 3,346,488, which is directed toamino methylene phosphonates as deflocculating agents and lrani et al.,U.S. Pat. No. 3,346,487, which is directed to the use of alkylenediphosphonates as deflocculating agents. Other common deflocculatingagents which have been used are polystyrene sulfonate, polyacrylic acid,polymethacrylic acid and napthaline sulfonate formaldehyde condensates.

While most of the above dispersants are effective, many of them sufferfrom one or more drawbacks. For example, a deflocculating agent shouldbe hydrolytically stable. However, it is well known that the inorganicpolyphosphates are hydrolytically unstable. In addition, otherdeflocculating agents are not temperature stable and are subject toshear degradation. Finally, some of the prior art dispersants are not aseffective as desired.

Therefore, it is an object of this invention to provide an effectivedeflocculating agent which is hydrolytically stable, temperature stableand which has good shear stability.

v employed SUMMARY OF THE INVENTION We have found that certainwater-soluble amino diphosphonates are effective deflocculating agentsand are hydrolytically stable, temperature stable, and shear stable. Theamino diphosphonates of our invention are represented by the followingformula where R is an alkyl group of one to five carbon atoms, phenyl orbenzyl and where x is 0 or I and where each M is independently selectedfrom the group consisting of hydrogen, alkali metal, alkaline earthmetal, and ammonium such that the resulting phosphonate salt is readilywater soluble.

When at is 0, the compounds of our invention may be named as substitutedl-amino methane, 1-1, diphosphonic acid. For example, when R is phenyl,the compound is called 1, amino, 1 phenyl methane 1,1 diphosphonic acid(at amino benzyl diphosphonic acid). When x is l, the compounds of ourinvention may be named as substituted 1, amino methane 1,-l,-dimethylene-phosphonic acid. For example, when R is phenyl, the compoundis called l-amino, l-phenyl methane, l-l-dimethylene-phosphonic acid (aamino benzyl dimethylene phosphonic acid).

The amino diphosphonic acid compounds of our invention are not novel.For example, see Blaser et al. U.S. Pat. No. 3,303,139, which isdirected to the use of certain amino diphosphonates as metal complexingagents. See, also, U.S. Pat. Nos. 3,202,579; 3,317,346 and 3,446,582.However, heretofore these compounds have never been employed asdeflocculating agents.

There are many different methods for preparing the compounds of ourinvention as is known by one skilled in the art. Our invention isindependent of the method to prepare the applicable aminodiphosphonates. When at is 0, we have prepared the compounds byutilizing three different processes. The compounds were prepared byreacting an appropriate organic nitrile with a phosphorous trihalide inthe presence of acetic acid. Then this intermediate was hydrolyzed withwater to yield the amino diphosphonic acid. We have also prepared thecompounds by reacting the organic nitrile with an alcohol to form animino ether which was then reacted with a phosphite and hydrolyzed toyield the amino diphosphonic acid. Finally, we have prepared thesecompounds by reacting an acid chloride with a phosphite and ammonia andthen hydrolyzing the intermediate reaction product to obtain the aminodiphosphonate. When x is l, we have the solids to be dispersed. Themaximum amount used will largely be an economic consideration. However,we have found that for. all practical purposes concentrations greaterthan 2.5 percent by weight will seldom, if ever, be used. While the useof about 0.01 percent by weight amino diphosphonate will give animprovement over systems without any deflocculating'agent, we have ifound that for most practical applications at least 0.1 percent isnecessary to show a commercially appreciable effect. Preferably, ouramino diphosphonates are used at a concentration of from about 0.1percent to 1.0 percent by weight. In addition, the concentration of theaqueous dispersion may vary over a wide range. The dispersion maycontain anywhere up to 70 percent or more by weight of .the finelydivided solids.

As is recognized by one skilled in the art, the actual concentration ofdeflocculating agent needed to effectively disperse the solids willdepend on such factors as the aqueous system being treated, the solidsbeing deflocculated, the viscosity desired, the presence or absence ofcontaminants, and the particular amino diphosphonate being used. Theconcentration ranges given are therefore only a general indication ofthe concentrations needed. The exact concentration must be determined byan examination of the variables of the system to be deflocculated.

We have found that the deflocculating agents of our invention may beused for dispersing many different finely divided solids in water.Illustrative but not limiting such finely divided solids are the coals(lignite, bituminous, anthracite), bauxite, fullers earth, ferric oxide,calcium carbonate, zinc oxide, zinc chromate, zinc sulfide, titaniumdioxide and many other well-known pigments and clays.

The deflocculating agents of our invention may be added to the finelydivided solids by any of a number of different methods as is recognizedby one skilled in the art. Our invention is independent of the method ofaddition so long as the compounds .are within the desired concentrationrange. For example, the amino diphosphonate may'be added to an aqueousslurry of the finely divided solids as a dry solid or as an aqueoussolution of the diphosphonate. The amino diphosphonate may be admixedwith the finely divided solids to form a dry solid admixture which. isthen dispersed in the aqueous medium. Alternatively, the dry aminodiphosphonate and the finely divided solids may be simultaneously addedto the aqueous medium. There are many other methods of addition whichmay be envisioned by the skilled artisan and which will work aseffectivelyas the ones mentioned above. The ultimate method chosen willlargely be an engineering decision. s

We have performed numerous experiments which demonstrate theeffectiveness of our compounds for deflocculating finely divided-solids.In addition, for comparison purposes we have performed the sameexperiments using some of the prior art deflocculants.

A series of dispersions were prepared using 390 grams of kaolin clay(non-predispersed kaolin clay obtained from J. M. Huber Corporation) and210 grams of distilled water and various amounts of the differentdeflocculating agents. This gave a dispersion of about 65 percentsolidspThe dispersions were prepared by placing the water in a widemouth quart jar and then adding the deflocculating agent and adjustingthe pH to 8 to 9 with dilute ammonium hydroxide, if necessary. A Cowlesdispersator was placed in the jarto provide the shear necessary forpreparing effective dispersions. The clay was then added over a fifteenminute period with moderate agitation. After the clay was added theTABLE 1 storage concentration in time viscosity deflocculating agentpercent by wt. in days in cps Calgon (sodium phosphate glass) 0.25 0 1750.25 I 7 [4,750 0.25 13 28,000 0.25 21 dilatant 0.50 0 150 t 0.50 7 3500.50 13 425 0.50 21 975 0.50 30 875 N-(pentamethylenephdtdiethylenetriamine 0.75 0 v 410 0.75 10 5,300 0.75 16 7,800 0.75 23 1L200 0.75 31 19,250 sodium polymethacrylate 0.75 0 I 0.75 9 L325 0.75 175 ,700 1.0 O 50 L0 9 dilatant alpha aminobenzyl diphosphonic acid(sodium salt) 0.5 0 60 0.5 6 60 0.5 l3 240 0.5 17 settled out 0.25 00.25 6 0.25 l3 240 0.25 l7 440 0.25 30 900 The results in Table 1illustrate that the compositions of our invention are effectivedeflocculating agents. Moreover, the tables indicate that our compoundsare hydrolytically stable, temperature stable, and shear stable. Theyare also more effective than many of the prior art compounds.

Another series of kaolin clay dispersions were prepared using thetechnique described above and vari ous deflocculating agents of ourinvention. The dispersions were stored for one month or longer at 65C.The results are shown in Table 2.

TABLE 2 storage concentration in time viscosity deflocculating agentpercent by Wt. in days in cps Alpha aminobenzyl diphosphonic acid(sodium salt) 0.25 0 460 0.25 7 1,050 0.25 14 1,500 0.25 21 8,000 0.2528 dilatant Alpha aminobenzyl di hosphonic acid (lithium salt) 0.25 0 500.25 7 75 0.25 14 150 0.25 21 100 0.25 28 150 0.25 35 350 0.25 42 4500.25 49 1,000 Alpha aminobenzyl dimethylene phosphonic acid (sodiumsalt) 0.5 0 75 0.5 7 75 0.5 I4 75 0.5 2! 75 0.5 28 75 The results ofTable 2 also clearly illustrate that our compounds are effectivedeflocculating agents and are temperature stable and hydrolyticallystable.

A series of dispersions were prepared using our deflocculating agentsand clay. The dispersions were evaluated by the Rohm and Haas pigmentdispersant procedure described in the Rohm and Haas Resin Review, Vol.XVIII, No. 3, Page 9. The results are shown in Table 3.

TABLE 3 concentration in deflocculating agent percent by wt. viscosityin cps Alpha aminobenzyl diphosphonic acid (sodium salt) 0.25 400Lithium salt 0.25 50 Ammonium salt 0.5 610 Alpha aminobenzyl dimethylenephosphonic acid (sodIum salt) 0.5 75

In addition to the data in the above tables, we have tested othercompounds of our invention on various other finelydivided solids. Forexample, we have found that 1 amino 1 methyl methane l,l diphosphonicacid and its water-soluble salts (a aminoethane diphosphonic acid)v arevery' effective deflocculating agents for calcium carbonate. I

Our compounds are also effective deflocculating agents for water-basedlatex paints. Various levels of our amino diphosphonates substitutedinto typical paint formulations for the presently used deflocculatingagent will yield acceptable commercial paints. An example of one of thepaint formulations is a high quality white topcoat comprising 67 gramsof water, 8 to 13 grams of amino diphosphonate deflocculating agent, 2grams of a nonionic surfactant, 1 gram of an antifoam agent, 20 grams ofethylene glycol, 1.4 grams of a biocidal preservative, 76 grams of a 2.5percent by weight aqueous solution of hydroxy ethyl cellulose, 192 gramsof non-chalking rutile titanium dioxide, 8 grams of free chalkinganatase titanium dioxide, 80 grams of talc, 89.5 grams of calciumcarbonate, 398 grams of Rhoplex AC-35, 5.6 grams of pine oil and 1.6grams of ammonium hydroxide. An example of another paint formulation isa vinyl chloride-acrylic exterior white house paint comprising 108 gramsof water, 204 grams non-ionic surface active agent, 16 grams of ethyleneglycol, 4.4 grams of amino methyl propanol, 5 to 9 grams of aminodiphosphonate deflocculating agent, 4 grams antifoaming agent, 20 gramsof anatase titanium dioxide, 112 grams of Nyt al'300, 190 grams ofTitanox RA-SO, .grams of a 2% percent kilogram weight solution ofhydroxyethyl cellulose and 77 grams of BFG-I2273 (Long Oil Alkydintermediate). The above two examples illustrate that our aminophosphonates will be effective deflocculating agents for water-basedpaints.

The compounds of our invention are also effective deflocculants for claydrilling muds. They are compatible with most additives used in claydrilling muds such as salt, caustic soda, soda ash, lime, gypsum cement,and weighting agents such as iron oxide.

As mentioned previously, the amino diphosphonates of our invention areparticularly suited for preparing pigment and clay slurries for use inpaper coatings. Our compounds are especially effective in preparing highsolids, low viscosity slurries of the pigments and clays used in thepaper coating field. Some of the more common clays and pigments used inpaper technology which our amino diphosphonates will deflocculate aretitanium dioxide, calcium carbonate, talc, silica, basic lead silicate,and zinc oxide.

We claim:

1. An aqueous dispersion comprising finely divided solids dispersed inan aqueous medium with a water where R is selected from the groupconsisting of alkyl groups of one to five carbon atoms, phenyl andbenzyl, x is O or 1 and each M is independently selected from the groupconsisting of hydrogen, alkali metal, alkaline earth metal and ammonium.

2. An aqueous dispersion as in claim 1 wherein the finely divided solidsare comprised of kaolin clay.

3. An aqueous dispersion as in claim 1 wherein the amino'diphosphonateis present inconcentrations of from 0.01 to-about 2.5 percent by weightbased on the weight of the finely divided solids.

4. An aqueous dispersion as in claim 1 wherein the amino diphosphonateis aminobenzyl diphosphonic acid.

5. An aqueous dispersion as in claim 1 wherein the amino diphosphonateis aminobenzyl dimethylene phosphonic acid.

6. An aqueous dispersion comprising kaolin clay dispersed in an aqueousmedium with from 0.1 to 1.0 percent by weight based on the weight of thekaolin clay of a water-soluble amino diphosphonate deflocculating agentof the formula where R is selected from the group consisting of alkylgroups of one to five carbon atoms, phenyl and benzyl, x is or 1 andeach M is independently selected from the group consisting of hydrogen,alkali metal, alkaline earth metal and ammonium.

7. Method of preparing a stable aqueous dispersion of finely dividedsolids comprising dissolving in the aqueous medium a water-soluble aminodiphosphonate of the formula

1. An aqueous dispersion comprising finely divided solids dispersed inan aqueous medium with a water-soluble amino diphosphonatedeflocculating agent of the formula where R is selected from the groupconsisting of alkyl groups of one to five carbon atoms, phenyl andbenzyl, x is 0 or 1 and each M is independently selected from the groupconsisting of hydrogen, alkali metal, alkaline earth metal and ammonium.2. An aqueous dispersion as in claim 1 wherein the finely divided solidsare comprised of kaolin clay.
 3. An aqueous dispersion as in claim 1wherein the amino diphosphonate is present in concentrations of from0.01 to about 2.5 percent by weight based on the weight of the finelydivided solids.
 4. An aqueous dispersion as in claim 1 wherein the aminodiphosphonate is aminobenzyl diphosphonic acid.
 5. An aqueous dispersionas in claim 1 wherein the amino diphosphonate is aminobenzyl dimethylenephosphonic acid.
 6. An aqueous dispersion comprising kaolin claydispersed in an aqueous medium with from 0.1 to 1.0 percent by weightbased on the weight of the kaolin clay of a water-solublE aminodiphosphonate deflocculating agent of the formula where R is selectedfrom the group consisting of alkyl groups of one to five carbon atoms,phenyl and benzyl, x is 0 or 1 and each M is independently selected fromthe group consisting of hydrogen, alkali metal, alkaline earth metal andammonium.
 7. Method of preparing a stable aqueous dispersion of finelydivided solids comprising dissolving in the aqueous medium awater-soluble amino diphosphonate of the formula where R is selectedfrom the group consisting of alkyl groups of one to five carbon atoms,phenyl and benzyl, x is 0 or 1 and each M is independently selected fromthe group consisting of hydrogen, alkali metal, alkaline earth metal andammonium.
 8. Method of claim 7 wherein the finely divided solids arecomprised of kaolin clay.